<template>
  <div class="tags" v-if="showTags">
    <ul>
      <li class="tags-li" v-for="(item,index) in tagsList" :class="{'active': isActive(item.path)}" :key="index">
        <router-link :to="item.path" class="tags-li-title">
          {{item.title}}
        </router-link>
        <span class="tags-li-icon" @click="closeTags(index)"><i class="el-icon-close"></i></span>
      </li>
    </ul>
    <div class="tags-close-box">
      <el-dropdown @command="handleTags">
        <el-button size="mini" type="primary">
          标签选项<i class="el-icon-arrow-down el-icon--right"></i>
        </el-button>
        <el-dropdown-menu size="small" slot="dropdown">
          <el-dropdown-item command="other">关闭其他</el-dropdown-item>
          <el-dropdown-item command="all">关闭所有</el-dropdown-item>
        </el-dropdown-menu>
      </el-dropdown>
    </div>
  </div>
</template>

<script>
import bus from './bus'

export default {
  data () {
    return {
      tagsList: []
    }
  },
  methods: {
    isActive (path) {
      return path === this.$route.fullPath
    },
    // 关闭单个标签
    closeTags (index) {
      const delItem = this.tagsList.splice(index, 1)[0]
      const item = this.tagsList[index] ? this.tagsList[index] : this.tagsList[index - 1]
      if (item) {
        delItem.path === this.$route.fullPath && this.$router.push(item.path)
      } else {
        this.$router.push('/')
      }
    },
    // 关闭全部标签
    closeAll () {
      this.tagsList = []
      this.$router.push('/')
    },
    // 关闭其他标签
    closeOther () {
      const curItem = this.tagsList.filter(item => {
        return item.path === this.$route.fullPath
      })
      this.tagsList = curItem
    },
    // 设置标签
    setTags (route) {
      const isExist = this.tagsList.some(item => {
        return item.path === route.fullPath
      })
      if (!isExist) {
        if (this.tagsList.length >= 8) {
          this.tagsList.shift()
        }
        this.tagsList.push({
          title: route.meta.title,
          path: route.fullPath,
          name: route.matched[1].components.default.name
        })
      }
      bus.$emit('tags', this.tagsList)
    },
    handleTags (command) {
      command === 'other' ? this.closeOther() : this.closeAll()
    }
  },
  computed: {
    showTags () {
      return this.tagsList.length > 0
    }
  },
  watch: {
    $route (newValue, oldValue) {
      this.setTags(newValue)
    }
  },
  created () {
    this.setTags(this.$route)
    // 监听关闭当前页面的标签页
    bus.$on('close_current_tags', () => {
      for (let i = 0, len = this.tagsList.length; i < len; i++) {
        const item = this.tagsList[i]
        if (item.path === this.$route.fullPath) {
          if (i < len - 1) {
            this.$router.push(this.tagsList[i + 1].path)
          } else if (i > 0) {
            this.$router.push(this.tagsList[i - 1].path)
          } else {
            this.$router.push('/')
          }
          this.tagsList.splice(i, 1)
        }
      }
    })
  }
}

</script>

<style>
  .tags{
    position:relative;
    height:30px;
    overflow:hidden;
    background:#fff;
    padding-right:120px;
    box-shadow:0 5px 10px #ddd;
  }

  .tags ul{
    box-sizing:border-box;
    width:100%;
    height:100%;
  }

  .tags-li{
    float:left;
    margin:3px 5px 2px 3px;
    border-radius:3px;
    font-size:12px;
    overflow:hidden;
    cursor:pointer;
    height:23px;
    line-height:23px;
    border:1px solid #e9eaec;
    background:#fff;
    padding:0 5px 0 12px;
    vertical-align:middle;
    color:#666;
    -webkit-transition:all .3s ease-in;
    -moz-transition:all .3s ease-in;
    transition:all .3s ease-in;
  }

  .tags-li:not(.active):hover{
    background:#f8f8f8;
  }

  .tags-li.active{
    color:#fff;
  }

  .tags-li-title{
    float:left;
    max-width:80px;
    overflow:hidden;
    white-space:nowrap;
    text-overflow:ellipsis;
    margin-right:5px;
    color:#666;
  }

  .tags-li.active .tags-li-title{
    color:#fff;
  }

  .tags-close-box{
    position:absolute;
    right:0;
    top:0;
    box-sizing:border-box;
    padding-top:1px;
    text-align:center;
    width:110px;
    height:30px;
    background:#fff;
    box-shadow:-3px 0 15px 3px rgba(0, 0, 0, .1);
    z-index:10;
  }

</style>
